I. Characterization of the T cell populations reactive in the AMLR A. Development of new monoclonal antibodies which recognize determinants expressed uniquely or differentially on T cells by using AMLR-stimulated peripheral blood lymphocytes (PBL) or AMLR-stimulated (IL-2 dependent) T cell lines as immunogens. B. Examination of the functional importance of the cells recognized by such antibodies (as in IA above) by a variety of in vitro assays. C. Biochemical and functional characterization of surface structures identified by such antibodies. II. Characterization of autoreactive T cell clones A. Development of autoreactive T cell clones derived from antigen-stimulated populations of T lymphocytes. B. Characterization of such clones in a variety of in vitro assays and use of these clones as immunogens to produce monoclonal antibodies (as in section I above). III. Analysis of an antigen found on mature T cells recognized by the monoclonal antibody, anti-T12 (see section IV.3 of progress report summary), involving analysis of anti-T12 treated cells in various in vitro assays and use of whole antibody, as well as Fab and F(ab')2 reagents.